Wheel Center Bore Comparator
Compare a wheel's center bore with the vehicle's hub diameter. Find the gap and the hub-centric ring size needed, in mm and inches.
Compare hub and center bore dimensions.
Wheel Center Bore Comparator: Tire Size Inputs
Compare two tire sizes here. Use the formulas and reference tables below for this tool's specific calculation.
How Wheel Center Bore Comparator Works?
The Wheel Center Bore Comparator works by subtracting the hub diameter from the wheel's center bore and naming the hub-centric ring that fills the gap. The tool uses 3 steps.
Enter the hub diameter
Type the vehicle's hub pilot diameter, for example 66.6 mm.
Enter the wheel bore
Type the wheel's center bore, for example 72.6 mm.
Read the result
The comparator returns a 6.0 mm (0.24 in) gap and a 72.6 mm OD × 66.6 mm ID hub-centric ring. A bore smaller than the hub returns Does not fit.
Wheel Center Bore Comparator Formula
The Wheel Center Bore Comparator formula is Gap = Bore_wheel − Hub_vehicle, and the ring size is OD = Bore_wheel, ID = Hub_vehicle.
Δ = D_bore − D_hubΔ_r = Δ ÷ 2Δ ≥ 0 required ; Δ > 0 → ring needed- D_bore
- Wheel center bore (mm)
- D_hub
- Vehicle hub pilot diameter (mm)
- Δ_r
- Gap on each side of the hub (mm)
Worked example
A wheel with a 73.1 mm bore on a 60.1 mm hub leaves a 13.0 mm gap (6.5 mm per side). The correct ring is 73.1 mm OD × 60.1 mm ID.
Wheel Center Bore Comparator Conversion Table
The Wheel Center Bore Comparator conversion table lists the gap and hub-centric ring size for 8 common hub and bore pairs.
| Hub diameter | Wheel bore | Gap | Ring needed |
|---|---|---|---|
| 57.1 mm (2.248 in) | 72.6 mm | 15.5 mm | Ring 72.6 OD × 57.1 ID |
| 60.1 mm (2.366 in) | 73.1 mm | 13.0 mm | Ring 73.1 OD × 60.1 ID |
| 64.1 mm (2.524 in) | 73.1 mm | 9.0 mm | Ring 73.1 OD × 64.1 ID |
| 66.6 mm (2.622 in) | 72.6 mm | 6.0 mm | Ring 72.6 OD × 66.6 ID |
| 67.1 mm (2.642 in) | 73.1 mm | 6.0 mm | Ring 73.1 OD × 67.1 ID |
| 70.5 mm (2.776 in) | 74.1 mm | 3.6 mm | Ring 74.1 OD × 70.5 ID |
| 72.6 mm (2.858 in) | 72.6 mm | 0.0 mm | Exact fit |
| 78.1 mm (3.075 in) | 87.1 mm | 9.0 mm | Ring 87.1 OD × 78.1 ID |
What is Wheel Center Bore Comparator?
A Wheel Center Bore Comparator is a tool that checks whether a wheel's center hole fits the vehicle's hub and sizes the ring that centers the wheel. Aftermarket wheels use large bores, often 72.6 mm or 73.1 mm, to fit many vehicles.
A hub-centric fit centers the wheel on the hub and keeps the wheel concentric. A wheel without a ring depends on the lug seats alone, which often causes vibration at 50 to 70 mph (80 to 113 km/h).
A bore smaller than the hub never fits. Machining the bore larger is the only fix.
What are the uses of Wheel Center Bore Comparator?
There are 4 main uses of the Wheel Center Bore Comparator, including ring ordering and vibration diagnosis.
Ring ordering
Order the correct hub-centric ring size.
Vibration diagnosis
Check for a missing ring after new wheels cause shake.
Used wheel checks
Confirm a bore is large enough for the hub.
Spacer matching
Match a hub-centric spacer's bore and lip to the wheel.
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